1. Field of the Invention
The present invention relates generally to a structure of a sliding switch contact and, in particular, to a contact structure adapted for a sliding switch that is used in high-temperature oil.
2. Description of the Related Art
Switch contacts are conventionally made of copper alloys, which are excellent in electric characteristics and springiness. A conventional switch contact is disclosed, for example, by Japanese Unexamined Patent Publication No. S63-213221, wherein a copper alloy of a sheet material is employed to increase the mechanical strength for the switch contact. This conventional switch contact uses a technique wherein a spring alloy at its respective surfaces is superposed by a copper alloy to be subjected to roll working.
However, although the conventional copper switch contact possesses excellent properties as stated hereinbefore at room temperatures, there is a problem in that the switch contact loses its function of contact under temperatures conditions ranging from -40.degree. C. to 180.degree. C. in an oil within a vehicular transmission, an engine, a brake oil-pressure system, or the like. If copper or copper alloy is used as a slide contact under the aforesaid environment, insulating compounds, such as copper oxides and sulfides, are produced over the surface thereof in a short period of time and thereby cause a problem of electrical disconnection.